Ongoing challenges for organic light emitting diodes (OLEDs) for lighting applications include improving efficiency and stability of the devices. Phosphorescent dyes based on iridium have been used to achieve high efficiency OLEDs. Other classes of phosphorescent dyes that have been explored in the past include platinum- and europium-based materials, and there have been few successful efforts to design phosphorescent dyes based on other heavy metals. Therefore, there is a need for a new class of materials that can enable devices having improved efficiency and stability.